universe

Introduction

universe, totality of matter and energy in existence. The study of the origin of the universe, or cosmos, is known as cosmogony, and that of its structure and evolution, cosmology. The age of the universe depends on which theory of cosmology one accepts. According to the big bang theory, favored by most scientists, the universe is between 10 and 20 billion years old; most recent calculations place its age at c.13.75 billion years. The steady-state theory holds that the universe has been in existence for all time.